A Dormant Ruthenium Catalyst Bearing a Chelating Carboxylate Ligand: In Situ Activation and Application in Metathesis Reactions

In Situ Activation of a Latent Ruthenium–Carbene Complex in Ionic Liquid and Its Application in Ring‐Closing Metathesis

“…Nevertheless, the catalytic activity of the in situ activated ruthenium complex in IL was quite comparable or superior to those of the reported ruthenium complexes activated by using Brønsted acids. [6] …”

“…Ru complex 2 for this study was separately synthesized according to the reported procedure by Grela et al [6] The RCM of the benchmark substrate, N,N-bisallyl p-toluenesulfonamide (4a), was carried out at room temperature first with 2 (1.0 mol-%) in CH 2 Cl 2 /[bmim][SbF 6 ] (1:1) (bmim = 1-butyl-3-methylimidazolium). After 2 h reaction, less than 10 % conversion was observed ( Entries 3-5).…”

“…Grela and coworkers also recently reported the serendipitous finding of the same, catalytically inactive, Ru complex 2, which can be elegantly activated by treatment with Brønsted acids such as HCl to form Ru-dichloride complex 1c as a catalyst precursor. [6,7] In this communication, we report our successful and efficient, in situ activation of latent Ru complex 2 in an IL with the aid of imidazolium halide or tetrabutylammonium halide 3 ( Figure 1). Figure 1.…”

5.26 Cross Metathesis

“…The best catalysts were found to be Gru-II, Gre-II, and Carb-II. 26 Despite structural similarities between the utilized catalysts (Hov-II and Gru-II, Carb-II and Est-II) the reaction outcomes varied highly, suggesting an electronic effect as the cause of the observed differences. The study also pointed out that another method of increasing the conversion was the efficient removal of ethylene.…”

Latent ruthenium olefin metathesis catalysts featuring a phosphine or an N-heterocyclic carbene ligand

“…It has been demonstrated that the initiation can be controlled by, for example, irradiation (eq 1) [4] or addition of acid (eq 2) [5, 6,7,8].…”